JPS62197014A - Relay driving apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a relay drive device for controlling a heating control relay, etc. of a jar rice cooker.

<Prior Art> In a rice cooker equipped with a jar rice cooker, the overheating of the heater is controlled by a relay. However, during heating, the temperature around the control unit may rise to about 70°C. Therefore, it is necessary to minimize the temperature rise of the electronic components of the control section.

The operating voltage range of the control relay becomes narrower as the ambient temperature increases. On the other hand, as the ambient temperature rises, the relay coil resistance increases and the voltage across the coil increases.

In the past, a high constant voltage was always applied as the coil voltage so that the relay would operate even at high temperatures, so when the temperature of the fill increased rapidly and the ambient temperature became high,
Sometimes the parts' ratings were exceeded. Furthermore, power consumption also increased.

<Purpose> In view of the above, when a relay is operated by an output signal from a control circuit, the present invention first turns on the drive circuit sufficiently for longer than the operation time of the relay, and then turns the drive circuit on and off.
It is an object of the present invention to provide a relay drive device that can reduce the effective value of the normal pressure applied to the relay coil by FF, and suppress the rise in coil temperature and power consumption.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3. A relay drive device according to the present invention includes a relay coil 2a for controlling energization of an electric rice cooker heater 1 and a relay contact 2b. A relay 2 comprising: a drive circuit 3 for driving the relay 2; and a control circuit 4 for outputting a control signal to the drive circuit 3; A function to output an ON signal longer than the operating time to the drive circuit 3, and a signal to turn the drive circuit 3 ON-0 and FF so as to apply a voltage equal to or higher than the relay contact holding voltage of the relay 2 after the contact operating time has elapsed. It has the function of outputting.

FIG. 2 is an electric circuit diagram of a heater such as a jar rice cooker, in which a rectifier circuit 9 (bridge circuit) is connected to an AC power source 7 via a transformer 8, and a constant voltage circuit 10 is connected to the rectifier circuit to control the above-mentioned. Circuit 4 is connected.

The control circuit 4 is a general one-chip microcomputer, has a program ROM, data RAM, ALU, etc. inside, is driven by a reference clock oscillator, and has an output for driving the drive circuit 3. It has a terminal 4a.

The drive circuit 3 includes a transistor 11, and the base side of the transistor 11 is connected to the output terminal 4a of the control circuit 4.
The collector side is connected to the relay coil 2a of the relay 2, and the emitter side is connected to the positive side of the constant voltage circuit 10.

Further, the rice cooking heater 1 is connected in series to the relay contact 2b of the relay 2.

In addition, 13 in FIG. 2 is a transistor of the constant voltage circuit 10,
Similarly, 14 is a Zener diode, 15 is a protection diode, and 16 is a varistor.

In the above configuration, in order to turn on the relay 2 for the first time, a voltage higher than the relay contact operating voltage must be applied to the relay coil 2a for longer than the contact operating time. After that,
If a voltage higher than the contact holding voltage is applied, the contact can be maintained in the ON state.

Therefore, by first applying a voltage higher than the contact operating voltage and then lowering it to the holding voltage, the temperature rise in the coil of the relay 2 can be alleviated.

FIG. 1 shows the control time chart, and FIG. 3 shows the control flow chart. In FIG. 2, by turning on and off the transistor 11, the relay 2 is turned on and off.
F. Therefore, as shown in FIG.
is turned on and this time is set as TA. After that, set Tri to O so that the OFF time is less than the contact return time B.
N-OFF, and let the times be TB and TC, respectively. In this case, the voltage applied to both ends of the relay coil 2a is reduced by half in terms of effective value.

By changing the period and ON-OFF time, the effective value can be changed, so the lightning IT applied to the coil 2a is reduced.71? Choose these optimal values as soon as possible.

In this way, it is possible to suppress the rise in temperature of the coil and further suppress the current consumption of the circuit.

Next, the control program of the control device will be explained based on the chart 70 in FIG. 3. When the rice cooking relay 2 is not turned on, the process goes through the route (1).

Enter the rice cooking mode and set the rice cooking relay O in the MAIN control section.
When deciding to start N, only at this time, that is, the initial state OF
When turning on rice cooking relay 2 that is F, use (2)
Input the relay ON time data TA to ensure that the relay contact 21 is ON in the counter T in the route of
Enter route (3) and turn on rice cooking relay 2. To turn on the rice cooking relay 2, a transistor ON signal is output from the output end 4a of the control circuit 4, and this control is made the main control.

In the main control, since the rice cooking relay is in ON mode, the counter T counts down.

In this case, the route (4) is entered, and when the relay ON time TA required to turn on the relay contact 2b reliably has elapsed and the value of the counter T becomes zero, the route (5) is entered. At this time, the output terminal 4a of the control circuit 4 is ON, so the relay OFF time data TB that can keep the relay contact 2b in the ON state is input to the counter T that enters the route (6). 4aeC) Return to route 4) via FFL and main control. When the relay OFF time TB during which the relay contact 2b can continue to be in the ON state has elapsed and the value of the counter T becomes zero, the route (5) is entered. At this time, since the output terminal 4a of the control circuit 4 is OFF, (7
) Enter the relay ON time data TC to keep the relay contact ON in the counter T that is entered into the route of (3).
), the output terminal 4a of the control circuit 4 is connected to ONL,
Return to route 4) via the main control. After that,
Periodically turn ON- so that the relay contact remains ON.
A relay drive signal that repeatedly turns OFF is output from the control circuit 4.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, although the relay drive device according to the present invention was used in a glossy rice cooker in the above embodiment, it can of course also be used in a pond heater, such as a microwave oven, an electromagnetic cooker, and the like. In this case, the relay would control the magnetron and heating filter, respectively, instead of the electric heater. Of course, the relay drive device cannot be used for pond purposes either.

Effects> As is clear from the above description, the present invention includes a drive circuit that drives an energization control relay consisting of a relay coil and a relay contact, and a control circuit that outputs a control signal to the drive circuit. The circuit has a function of outputting an ON signal longer than the relay contact operation time to the drive circuit at the time of the initial ON operation of the relay, and is driven to apply a voltage equal to or higher than the relay contact holding voltage of the relay after the contact operation time has elapsed. The present invention relates to a relay driving device characterized in that it has a function of outputting a signal for turning on and off a circuit.

Therefore, according to the present invention, when the relay is operated by the 8-power signal from the control circuit, the drive circuit is first turned ON for more than the relay operation time, and then the drive circuit is turned ON.
Since the effective value of the voltage applied to the relay coil is lowered by turning it off, the temperature rise of the coil and power consumption can be suppressed, and since the control is performed only by the output signal of the control circuit, cost increases can be suppressed. It has excellent effects such as being able to

[Brief explanation of drawings]

FIG. 1 is a time chart for relay control of a relay drive device showing one embodiment of the present invention, FIG. 2 is an electric circuit diagram of a heater such as a rice cooker, and FIG. 3 is a control flowchart thereof. 1: Heater, 2: Relay, 2a: Relay coil, 2b:
Relay contact, 3: Drive circuit, 4: Control circuit, 8 Nidorance, 9: Rectifier circuit, 10: Constant voltage circuit, 11: Transistor, 14: Zener diode, 15: Protection diode.

Claims (1)

[Claims] The control circuit includes a drive circuit that drives an energization control relay consisting of a relay coil and a relay contact, and a control circuit that outputs a control signal to the drive circuit. It has a function of outputting the above ON signal to the drive circuit, and a function of outputting a signal to turn the drive circuit ON and OFF so as to apply a voltage higher than the relay contact holding voltage of the relay after the contact operation time has elapsed. A relay drive device characterized by: